How to write address in ADDM function block

[Kik]

Hello everyone,

I'm trying to use some functions like READ_VAR or DATA_EXCH to communicate with modbus devices on my M340.

Before that, I have to use ADDM function and to write the address.

This my configuration:

I'm using the NOC card on port #2. I assume that my address will be:

192.168.180.6 is my modbus device that I want to target.

I tried :

• '0.2.2{192.168.180.6}0'
• '0.2.2{192.168.180.6}1'
• '0.2.1{192.168.180.6}'
• '0.2.2{192.168.180.6}'

But I think it doesn't work because I have no request (capturing with Wireshark).

Do you have any idea ?

Thanks

[Ricard]

Hello my friend @Kik ,

There was a problem uploading the images, can you upload them again?

BR

Ricard

[Fidencio]

The correct syntax for the address string is crucial for successful communication. The general format for the address string in ADDM is 'r.m.c{IP_Address}e', where r represents the rack number (typically 0 for the main rack), m is the module number (the slot where the NOC module is installed), c refers to the channel number (the Ethernet port on the communication module), IP_Address is the target Modbus device’s IP, and e is the equipment number, which is the Modbus Unit ID.

For example, if your NOC module is in slot 2 and you're using port 2, targeting a device at 192.168.180.6 with a Unit ID of 1, the correct address string would be '0.2.2{192.168.180.6}1'. If your Modbus device uses a Unit ID of 0, then the string should be '0.2.2{192.168.180.6}0'.

If you’re not seeing any communication requests in Wireshark, there are a few things to check. First, ensure that the IP settings of both the PLC and the Modbus device are correctly configured and within the same subnet. Also, verify that the NOC module is properly set up to communicate over the selected port. Additionally, make sure your Modbus device is powered on and ready to accept connections.

If the communication still doesn’t work, confirm the correct Unit ID of your Modbus device, as some devices might require a different number instead of 1 or 0. To further troubleshoot, try using tools like ModScan or Modbus Poll from a PC to check if the Modbus device is responding and whether the network path is clear.

[JerryBartlemay]

The channel designation in the r.m.c isn't the port number, it's the logical channel in the module.  In an M580 controller, for example, Ethernet messaging uses channel 3.  There is only one channel in the NOC, channel 0.  So the correct usage with an ADDM is '0.2.0{ip address}unit ID if used'.  For an ADDMX it would be '0.2.0.{ip address}unit ID if used'.  The period behind the r.m.c is an easily missed small difference.

[ismailozinan]

I shared my m340 program screen. it has been working since 2018. Could you please look over at attached.

[JerryBartlemay]

Hello Ismail,  Your logic looks fine.  Did you have a question on it?  The difference between what I see in the screen shot and the original question is the use of the Ethernet port configuration name instead of the r.m.c notation.  In M340, because we define a network, name it, and attach it to a module, we can use the name.  In either M580 or M340, the r.m.c notation works.

[ismailozinan]

No, I did not have a question. I answered based on the question title so that the answer would remain under the same title in case similar questions arise in the future.

[Rico94]

Hello all, can you define when use an ADDM instead ADDMX?thanks